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than the expected 1% is 2x 10-6. Recombination was detectedin 5 parents; it occurred in both fathers (families 75-12-4,75-12-8, 75-12-9) and mothers (families 75-12-9,75-12-10), and the crossovers separated HLA-A from HLA-Bin 3 cases and HLA-B from HLA-D in the other 3. The dataobtained suggest the existence of a gene which increases therate of recombination in at least a segment of human chromo-some 6 and which, when homozygous, may be associated withthe appearance ofj.D.M.

College of Physicians and Surgeonsof Columbia University andLindsley E. Kimball Research Instituteof the New York Blood Center,New York, N.Y., U.S.A.

NICOLE SUCIU-FOCAPABLO RUBINSTEIN

RISING RATES OF CONGENITAL DISLOCATION OFTHE HIP?

SIR The more than 20-fold increase in the reported fre-quency of congenital dislocation of the hip (C.D.H.) in Rehovotto which Professor Klingberg and his colleagues (Feb. 7, p.298) refer could be an artifact. The children concerned were"newborn", so one assumes that they were said to have C.D.H.disorder if a positive result was obtained on testing their hipsfor instability shortly after birth. The results obtained by dif-ferent observers with such tests vary widely, although most ifnot all have found that the proportion of tested infants inwhom the tests are positive is much higher than the proportionof untested children who eventually present with hip disloca-tion. In England, for example, before neonatal screening of thehips was introduced dislocation used to be diagnosed in onlyabout 0 1% of children,’ but one or both hips were reported tobe dislocated or dislocatable in 04% of infants screened within36 h of birthZ and in 1.5% screened during the first week oflife.3 Barlow3 found an even higher proportion of cases amongthose screened during the first 3y days, and he concluded thateven without treatment the hips must stabilise spontaneouslyin more than three-fifths of these cases within 1 week and inseven-eighths within 2 months of birth. The prevalencereported during the first 2 years of the Rehovot study (0-09%)is thus so low as to suggest that at this time the hips of mostnewborns were not being screened; and the subsequent rise (to2.1%) could have been due to screening being done increas-ingly often, increasingly early, and/or by observers who wereincreasingly ready to diagnose instability.Department of Community Medicine,University of Manchester,Stopford Building,Oxford Road,Manchester M13 9PT. IAN LECK

HYPERLIPOPROTEINÆMIA AND PSORIASIS

SIR,-Medical research sometimes follows a curiously cycliccourse: a topic is popular for a decade, loses its appeal, and then"rediscovery" stimulates another wave of interest. Dr Brusteinand his colleagues (Jan. 17, p. 154) report increases in blood-li-pid fractions in psoriasis and hope that their letter will "stimu-late further investigation." In 1961 Tickner’ listed three publi-cations dealing with total lipid, seven on lipoprotein, and twelvereporting cholesterol serum levels in this disease. Would-be investigators should read Tickner’s conclusions before

reaching for their test-tubes.

Department of Dermatology,University of Nijmegen,Netherlands PAUL D. MIER

1. Leck, I., Record, R. G., McKeown, T., Edwards, J. H. Teratology, 1968, 1,263.

2. Finlay, H. V. L., Maudsley, R. H., Busfield, P. I. Br. med. J. 1967, iv, 377.3. Barlow, T. G. J. Bone Jt Surg. 1962, 44B, 292.4. Tickner, A. Br. J. Derm. 1961, 73, 87.

SIGNIFICANCE OF XANTHELASMAPALPEBRARUM IN THE NORMAL POPULATION

SIR A health survey in Iceland’ revealed 46 women and 11men with xanthelasma palpebrarum. The participants wereaged 34-64 and were selected from the national roster, and theresponse-rate was about 71%. The females examined num-bered 4303, the males 4063, giving prevalences of xanthelasmapalpebrarum of 1 1 % and 0-3%, respectively. The records ofthese people have been studied and compared with age and sexmatched controls, drawn from the same survey by the nearestnational roster number.

There was no difference between these two groups in thenumbers of positive answers to questions relating to family his-tories of diabetes mellitus, cerebrovascular accident, or ischa.mic heart-disease, or to questions relating to joint pains, mom-ing stiffness, or rheumatoid arthritis in the participantsthemselves. The two groups were comparable for weight, andsmoking habits were not significantly different.The occurrence of abnormal electrocardiograms (Minnesota

code) was not significantly different, and there was a compar-able frequency of arcus senilis (32% in both groups).No significant differences were found for fasting levels of

plasma cholesterol, triglycerides, bilirubin, alkaline phospha-tase, and uric acid or for erythrocyte-sedimentation rate, andthe outcome of 50 g glucose-tolerance test was comparable inboth groups.

It would seem, therefore, that the chance finding of xanthe-lasma palpebrarum in an Icelandic adult gives no hint of otherorganic or metabolic disturbance.Icelandic Heart Association,Heart Preventive Clinic,Lágmúli 9, Reykjavik, Iceland.

’ARSAELL JÓNSSONNIKULÁS SIGFÚSSON

ELECTROLYTE DISTURBANCES IN BEERDRINKERS

SIR We have seen a case of the hypo-osmolality syndromein beer drinkers described by Hilden and Svendsen. 2A 66-year-old man presented in October, 1975, with weak-

ness of the legs and mild dyspnoea. His only medication was aniron preparation. His diet was meagre, and he subsisted ontwelve cans of beer daily (about 4 litres). Total fluid intakedaily was about 5 litres. He used little salt.

Vital signs normal. Weight 117 kg. Abdomen obese, and 1+pitting pretibial and pedal oedema was present. No signs ofcirrhosis. Mild confusion cleared after a few days. Serum elec-trolyte findings (mmol/1) were:Electrolyte Hospital day

1 3 5 7 9Na 106 114 123 132 134K 3-8 2-9 3.0 3-9 4.0Cl 67 68 75 85 90

Most other routine laboratory tests were normal. The E.c,G,showed only mild prolongation of the P-R interval. Creatinineclearance was 56 mvniin. Serum osmolality was 218 mosmoUland urinary osmolality was 199 mosmol/1 on day 3. Urinesodium concentration was 56 mmol/1 and potassium 23mmol/1 on day 4 (12 h collection).

Fluids were restricted and the patient was put on a generaldiet unrestricted in sodium. Oral potassium chloride andspironolactone were given. He lost over 5 kg. His weaknessprogressively improved.We thought his hyponatraemia was partly dilutional, because

of his oedema, and partly due to a deficit in sodium as suggestedby the history of low sodium intake and the measured lowurine sodium. Beer drinkers can ingest a larger fluid load thanmost non-beer drinkers can comfortably accommodate. The

1. Allander, E., Björnsson, O. J., Kolbeinsson, A., Olafsson, O., Sigfusson, NThorsteinsson, J. Int. J. Epidem. 1972, 1, 211.

2. Hilden, T., Svendsen, T. L. Lancet, 1975, ii, 245.